On 11/16/2013 11:38 AM, Steve Newcomb wrote:
> On 11/15/2013 10:10 PM, John Cowan wrote:
>>
>>
>> On Fri, Nov 15, 2013 at 4:32 PM, Steve Newcomb <
>> <mailto:>> wrote:
>>
>> The DTD syntax was never about machines. It was about human beings, and
>> it is still, even today, and as crummy as it is, the most humane way
>> available for human beings to communicate about data design in a diverse
>> collaborative environment that inevitably must include non-programmers.
>>
>>
>> In my opinion, RELAX NG compact syntax is far more humane than DTDs. It
>> is as readable, if not more so; it has greater power; it has far fewer
>> arbitrary restrictions.
> It is *more* readable for you and for me. It is *less* readable for
> those who haven't yet fully internalized that XML schemas are all about
> element types. For us,
Wow - Steve I love your analogy, but I think you may have fallen in love
with it for its own sake, because it just doesn't apply to the DTD/RNC
comparison, at least I don't see it. Now I may be a high priest and out
of touch, but I just don't think DTDs are as transparent or accessible
as you seem to think they are.
Years ago, as a relative newcomer to these technologies, I looked at DTD
and RNC, and RNC made immediate, intuitive sense to me in a way that
DTDs did not (and probably never will, because I doubt I'll spend enough
time looking at them to get used to the squonks). Now that's a
completely subjective assessment, but for example consider the alien
words and tokens you have to learn to really get DTDs:
You have to understand that % is a magic letter that means the following
token doesn't really mean anything about the markup, but is a reference
to something defined elsewhere.
#IMPLIED (what does that mean? it seems to indicate there is a default
value, but what is it?
NMTOKEN (hunh?)
CDATA (wha?)
PCDATA (seems to have something to with CDATA, but is it different in
some subtle and important way?)
special meaning of ID/IDREF, but unfamiliar semantics (IDs can't be
numbers! that will surprise a lot of people)
What is that PUBLIC identifier in the DOCTYPE declaration anyway? It
often seems to have important-looking slashes and dashes in it, but
why? Do I need to conform to some kind of slash-and-dash convention
when inventing my own?
Contrived sure, and not all of these things are *necessary* in DTDs, but
typically one does encounter them. Sure Relax has its own syntax to
learn, but at its simplest, the RNG document structure *mirrors the
structure of the document it models*, which to me is the thing that
really makes it accessible and intuitive. I also like the relative lack
of obscure words. And I have to say that most of the people that I work
with have reacted in a similar way.
I like the idea that redundancy provides humans extra cues, but I'm just
not sure DTD format in itself actually provides that. Comments in human
languages are super helpful, as usual, but of course you can have
comments in any schema format.
-Mike
